Mathematic and scientific instrument maker and supplier, originally a partnership formed in 1878 between Joseph Halden and A.G. Thornton. It did not last long and each went their own separate ways, Halden setting up in new premises in Albert Square. The company prospered and after Joseph retired it is assumed his son took over the business. As well as selling wholesale, drawing and surveying instruments the company also patented its own designs for equipment. The company acquired other larger premises until by 1920 it had other showrooms in the main cities in United Kingdom. It produced the Calculex, a circular calculator which was considered the cheapest and most serviceable model at the time. The company continued to be run by members of the family until the untimely death of J.L. Halden in 1965 after which Managers from the company continued to run it until 1969 when it was taken over by the Ozalid Group.